Process of manufacturing beet sugar



March 30,1926. '1,578,463 4 E. E. NICHOLSON` ET AL PROCESS OF MANUFACTURING BEET SUGAR Filed oct. 6, i924 tub m precipitatedl are onlyA insoluble jinalkaline solutions, the -lrst treatment of carbon diox'- ide is lstopped, while there is still an ab1 1n 'E dance of caustic lime, present. Otherwise the' reaction would beireversibl'e. The substance' j is then passed'through a iilt'er-press andl a second carbonation reduces-the amount'of' free lime precipitatingcalcium carbonate,

l lPatented nnwnnnmmcnonson Nn man anaal., or .nmimuomalnmnsora To all vitant t Be it known that vvd-EDWARD E. N1cHo'L- soN and RALPH, B. BnAn, citizens of the United States, 4residing .at Minneapolis, in

thei county of- Hennepin and State :of Minnesota, have invented certain 'new ,anfd usel ul Improvements -in Processes of Manufacturing'Beet Sugar; and we do herebyde-x clare the following to 'be a full, clear, and

exact description of the invention, such as will enable others skilled in theart to which itappertains to make and use the same.

i-process of manufacturing cane sugar, it'isl particularly designed forI use inthe-manu- VThis invention 4relates to. an improved process in the 4manufacture of sugar and While the invention is also-applicable .to the facture of sugar from suga1 beets.

"' 'At present, the manufacture of beet sugar isj'fpactically standardized, although there may be briefly described :1s-follows;-

sugar diffusing through the cell' walls vof but largeamounts ofundesirable acid `ca'r- The sugar` beets, after being properly cleaned and cut into thin slices,` 'called cosettes,`ar e immersed in warm water, the

i n'the root into the water, Which'operation' is Y' i a ain filtered, and is often subjected to sul-'- 5v Pi 35,' carried out in a series' of-.tanks calledv a.

diusionbattery varranged in a circlegand 'connectedtdgether. The juice passes'loon# itinuouslyin -circulationthroughout these;r

tanks .growingeontinuously richer iny sugar.

After leaving the 'diffusion battery, the juice lis treated with. quantities o f'caustic lime,- Which treatmentis operative toneutralizeand precipitate the organicacids4 present. f A small amount of carbon dioxide is usu V ally added at this timelto 'decrease theexcess of lime, but since some, `of the `impurities magnesium and iron carbonates l'andV other insoluble carbonates,but still leaving traces ur dioxide fumes, to'remove-the alka1in ityn' thejsolution.4 step, however, is,

'P nocnsspr MANUFACTUMNG seamstress... i Appneaon cica catetere, 1924." 'serial im. '741,s7a j l i notlalways c lliployed.4 'Alfter fa third filtra-VY tion, the juice 1s' usually-evaporated, atlow temperature first, in a series of multi-tubular fat atmospheric pressure, is furthersulp'hured 'and filteredand'the evaporation concluded in steam heated vacuum-pans, In'the vacuumpans' or boiling.pans, crystallization-of the` i V sugar is slowly effected and vthe sug'lar then goes throu h the-centrifugals in w ich the crystallize sugarris'separated.. This fsugar f' is th'en driedand conveyed to-.thefgranm laters, where-it is si'fted and thenbagged for commercial use.

There are two outstanding objections to this. present process as above described First, v there is always considerable -diii'iculty in forcing the juice-through the filter presses after liming and' carbonation, because :of the-nature ofthe preci itates obtained. The

usual precipitates in t 'c process, as hithertol used, are not su'liiciently coarse or granular- Y to allow' the liquid "to -readilylpass through the filter pressV and are often sticky. The second objection `is that, after*A the second carbonation, -not only is free caustic lime necessarily left in thevsoluti'on,-

bonates, such as calcium 'acid carbonate' and magnesium, 'iron and other soluble carbonates still remailnl [These acid carbonates, as well .as the excess lime in solution, collect on'the walls of the evaporating tanks, vacuum pans'aud the hot pipes'throu h which said juice passes and is heated, an -form a y time mu'stnecessarily. be spent in removing rthis scaleyduring which Ithese importantl parts of the .apparatus`must remain idle,

thereby 'decreasing the output ofl theplant 4materially-' Y It i'sthe main object of thisinventionfto .to u sed.jI y `More specifically, it is an object of the. invention to treat' the'juice after the limin providejan iuprovedmethodlof manu-factur# an V,beeti 'su'gai", Wh1ch` will overcome the. above statedobjections to the proce'sshitherf L 'los with. sodiumfalminate. or other water so A vent jaluminatea 'whereby a portion of the;

excess of limemay beremoved together with no the precipitated o'rg"a`ni`c acids -infthe form of acoarse granu1ar "p1"ecipitate of floconadd to the filtered juice, afterthe last car-` bonation, further quantities of sodium aluminate to remove the last traces of lime in the solution Aand to break up the several soluble acid carbonates present therein, thus pre. venting the objectionable scaling onl the tanks and pipes of the evaporators and vaccum pans. The sodium aluminate removes practically all of these objectionable elements precipitating the sameand permitting them to be collected and thrown out in the next filtering step.

To these ends, generally stated, the invention consists of the novel process herein described and set forth in the claims.

The process may be carried o-ut by' any suitable apparatus, but, in order to make the :disclosure of the process more distinct, an apparatus suitable for carrying out the novel process is briefly diagrammed in the accompanying drawing.

' tank ,8. -Here under agitation,

In carrying out the process of the invention, the beets having been cleaned and weighed, are dropped through a chute 1 into a hopper 2 which feeds the slicing machine 3 provided with rotary cutters. The sliced beets pass through the chute 4L into the several tanks 5 of the battery and provision is made for unloading the sliced beets into the several tanks (not shown). lVarm water is. run over the sliced beets or cosettees, successively causing diffusion of the juices containing the sugar. The juice passes from the battery tol a measuring tank 6 and from there to the tank 7, where the juice is heated and passed tol the liming either by the steam in said tank, or by mechanical means, quantities of lime are run into the vliming tank 8 from the lime kiln 9. The

organic acids are precipitated and, after sufficient liming has taken place, small quantities of sodium aluminatel or Asome other water solvent aluminate are introduced into the tank 8 from the reservoir 10. The sodium aluminate is added during agita- 'tion of the liquids within tank 8 and precipitates a portion of the lime in the calcium aluminate also precipitating small amounts of magnesium, iron or other soluble hydroxides in solution. These precipitates formed have the peculiar characteristic of being made up of a plurality of coarse granular particles of flocculent shape. In the liming tank 8, before the sodium aluminate is admitted, it may be desirable` to admit a small quantity of carbon dioxide, although, preferably, this step is omitted. From the liming tank, the mass passes into the first filter press 11, where the precipitates are filtered out and the clear juice admitted to the carbonation tank` 12. The coarse irregular flakes of the precipitate produced permit a ready passage ofthe juicevthrough the filter press. There is still present an excess of lime in the resulting filtrate, since this is necessary to prevent a reversal of the chemical reaction and also to prevent the sugar from breaking down into its components, glucose and fructose, during the further process. In tank 12, large amounts of carbon dioxide, produced in the burning of the lime in the llime kiln tank, are intro- .duced passing through the pipes 13 into the juice in tank 12 and precipitating large amounts of calcium carbonate andI smaller amounts of magnesium, iron and other insoluble carbonates. The alkalinity of the solution is, of course, greatly reduced by the addition o f the carbon dioxide. The liquid is then again filtered through the filter press 14, admitting the filtrate to the tank 15.

The juice admitted to tank 15 contains traces of the lime as well asconsiderable' amounts offthe several acid carbonates necessarily formed in the carbonation process just described. These acid carbonates, as

well as the excess of lime, will collect and harden forming a hard scale on the tanks and pipes in the evaporators .and driers through which the juices pass later in the refinement. Considerable quantities of sodium aluminate are admitted to xthe tank 15 from vthe reservoir 10, which. precipitate the acid carbonates and also remove the remaining traces of lime from the solution.l By adding an excessof the sodium aluminate, practically all of these undesirable scaleforming chemicals are removed from l the solution and the liquid passes through the i filter 16 into the-evaporator 17 and through the heater 18. Before entering the evapor-A ator 17, it is preferable to treat the liquid with sulphur dioxide fumes to remove'the alkalinity caused by the sodium hydroxide left in solution after the sodium aluminate was added in tank 15. This step may, however, be carried out after the liquid has gone through the first evaporation tank.`4` The sulphur dioxide not only neutralizes the alkalinity but. also is instrumental to bleach the sugar. The juice is further evaporated,

crystallized and dried in the customary way by means not shown in the drawing.

The proportion of the sodium aluminate admitted in tank 8 will vary from one` tenth to three-fourths of a pound of 25% solution of sodium aluminate to the thousand j tetris gallonsv of the juice, depending upon the solution of caustic lime in this tank.

The amount of sodium aluminate admitted in tank 15, where the acid carbonates and excess of lime are removed, varies from onefourth to one and one-half pounds of 25% solution of sodium aluminate to the thousand gallons of liquid within this tank, depending, of course, on the condition of the juice when the sodium aluminate is admitted. rlhe best results are obtained within the range of these proportions. 4

From the above description, it will be seen that a novel and improved process has been invented, which does away with some of Y the most outstanding disadvantages in the present day manufacture of beet sugar.

In the tank 8, a portion of the excess of lime is removed and the character of the precipitate is materially changed from that of the old process hithertoused, towit: a coarser and more porous and brittle precipitate is effected, which will more readilyv permit filtration of the juices therethrough.

The objectionable scaling and incrustation of the several heated tanks, evaporators, vacuum pans and heated pipes have been obviat ed by the application of the sodium aluminate in the proc^ss, after carbonation and filtration of the juice.4

The employment of, this process., therefore,

results in not only an improved product but Vin a substantial increase in the daily output of the plant, speeding up filtration and obviating the necessity for the cleaning of the parts of the apparatus in which scaling is the raw products, treating said juice with an excess of caustic lime, adding a quantity of water soluble aluminate yto precipitate portions of the excess yof lime and other hydroxides present, for producing fioccular and granular precipitates, filtering the resulting mass and treating the filtrate with carbon dioxide, then further filtering said juice. 4

2. rlhe process of manufacturing sugar which comprises adding a quantity of water soluble aluminate to the juice from the raw materials after said juice has beentreated with caustic lime and carbon dioxide,'where by the remaining traces 'of lime and other hydroxides as Well as the soluble acid carbonates present in solution after said last two named steps will be precipitated, and filtering the resulting liquid therefrom.

3. The process of manufacturing sugar which comprises extracting the juice from the raw products, treating said juice with caustic lime, adding a quantity of water soluble aluminate, filtering the liquid, treating the filtrate ywith carbon dioxide and again filtering, then'adding a quantity of water soluble aluminate to said last named filtrate, and again filtering the juice.

4. The process of manufacturingbeet sugar which comprises extracting thejuice from `the sugar beets, treating said juice under agitation with an excess of caustic lime, addfifi ing a quantity of water soluble aluminate to thesolution after sufficient working of the lime to remove a portion of the excess of lime and other hydroxides present for .producinga coarse flocky and granular precipi tate adapted to permit speedy and efficient filtration, passing the juice through a filter press and treating the filtrate with quantities of carbon dioxide to precipitate calcium carbonate and other carbonates, again filtering the solution to remove the carbonate and other precipitates, and ladding a quantity of water soluble aluminateto the filtrate to 'remove the remaining traces of lime and `precipitate the acid carbonates formed in said last named step and again filtering.

5. A step in the process of manufacturing sugar which comprises adding quantities of water soluble aluminate to the limed and carbonated juice to remove excess calcium hydroxide and acid carbonates in the form of a coarse granular and flocky precipitate adapted to readily permit passage of the solution therethrough in the filter presses.

In testimony whereof we affix our signatures.

EDWARD E. NioHoLsoN. l RALPH B. BEAL. 

